Permafrost thaw lakes and ponds as habitats for abundant rotifer populations
Thermokarst lakes and ponds were sampled across a range of permafrost landscapes in subarctic Québec (Nunavik, Canada) to compare their rotifer and other zooplankton characteristics with a set of rock-basin lakes and ponds in the region. A total of 24 rotifer species were identified, with an average...
Published in: | Arctic Science |
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Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English French |
Published: |
Canadian Science Publishing
2018
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Subjects: | |
Online Access: | https://doi.org/10.1139/as-2016-0017 https://doaj.org/article/57f00f6c12474b23ba478a4800f33665 |
Summary: | Thermokarst lakes and ponds were sampled across a range of permafrost landscapes in subarctic Québec (Nunavik, Canada) to compare their rotifer and other zooplankton characteristics with a set of rock-basin lakes and ponds in the region. A total of 24 rotifer species were identified, with an average of seven taxa per waterbody. Rotifer abundance was an order of magnitude higher in the thaw ponds than in rock-basin waters. In some thaw ponds, rotifers accounted for >50% of the total zooplankton biomass, but for <10% in all of the rock-basin waters. Neither α- nor β-diversity was significantly different between the two waterbody types. Grazing experiments with microspheres (0.5–6 µm diameter) showed that medium-sized particles (2–3 µm) were preferred to smaller and larger particles; clearance rates were <0.05% of the water column per day, implying that the rotifer populations were unlikely to be bottom-up limited by food availability. Rotifer abundance was negatively correlated with cladoceran densities, suggesting possible interference effects. Chaoborus larvae were also present and may exert a top-down control. Thermokarst ponds are currently favorable environments for rotifers, but the rapid change they have begun to experience brings uncertainty about their ongoing capacity to sustain these prolific communities. |
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